Brigham and Women's Hospital
In a study of more than 5,000 people, investigators from Brigham
and Women's Hospital have found that greater intake of nuts was associated with
lower levels of biomarkers of inflammation, a finding that may help explain the
health benefits of nuts. The results of the study appear in the American
Journal of Clinical Nutrition.
"Population studies have consistently supported a
protective role of nuts against cardiometabolic disorders such as
cardiovascular disease and type 2 diabetes, and we know that inflammation is a
key process in the development of these diseases," said corresponding
author Ying Bao, MD, ScD, an epidemiologist in BWH's Channing Division of
Network Medicine.
"Our new work suggests that nuts may exert their beneficial effects in part by reducing systemic inflammation."
Previously Bao and her colleagues observed an association
between increased nut consumption and reduced risk of major chronic diseases
and even death, but few prospective cohort studies had examined the link
between nut intake and inflammation.
In the current study, the research team performed a
cross-sectional analysis of data from the Nurses' Health Study, which includes
more than 120,000 female registered nurses, and from the Health Professionals
Follow-Up Study, which includes more than 50,000 male health professionals.
The team assessed diet using questionnaires and looked at the
levels of certain telltale proteins known as biomarkers in blood samples
collected from the study participants. They measured three well-established
biomarkers of inflammation: C-reactive protein (CRP), interleukin 6 (IL6) and
tumor necrosis factor receptor 2 (TNFR2).
After adjusting for age, medical history, lifestyle and other
variables, they found that participants who had consumed five or more servings
of nuts per week had lower levels of CRP and IL6 than those who never or almost
never ate nuts.
In addition, people who substituted three servings per week of
nuts in place of red meat, processed meat, eggs or refined grains had
significantly lower levels of CRP and IL6.
Peanuts and tree nuts contain a number of healthful components
including magnesium, fiber, L-arginine, antioxidants and unsaturated fatty
acids such as α-linolenic acid.
Researchers have not yet determined which of these components,
or if the combination of all of them, may offer protection against
inflammation, but Bao and her colleagues are interested in exploring this
further through clinical trials that would regulate and monitor diet.
"Much remains unknown about how our diet influences
inflammation and, in turn, our risk of disease," said Bao. "But our
study supports an overall healthful role for nuts in the diet and suggests
reducing inflammation as a potential mechanism that may help explain the
benefits of nuts on cardiometabolic diseases."